Kate Gosselin Collin

Jon Gosselin is saying that he wants his ex-wife, Kate Gosselin, to be criminally charged ... after their son, Collin Gosselin, claimed Kate abused him when he was growing up.

Jon mentioned potential criminal charges when reacting to Kate's suggestion that Collin's claims were somehow influenced by a mental illness.

He told Entertainment Tonight ... "She needs to stop. He is not mentally ill. I would definitely have grounds to sue Kate for defamation and libel. I don't even think it's suing. I think it's just criminal charges. So, that's up to the state."